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Fixed bug #29104: assertion abort for grouping queries using views.

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The abort happened when a query contained a conjunctive predicate
of the form 'view column = constant' in the WHERE condition and 
the grouping list also contained a reference to a view column yet
a different one.

Removed the failing assertion as invalid in a general case.

Also fixed a bug that prevented applying some optimization for grouping
queries using views. If the WHERE condition of such a query contains
a conjunctive condition of the form 'view column = constant' and
this view column is used in the grouping list then grouping by this
column can be eliminated. The bug blocked performing this elimination.
This commit is contained in:
igor@olga.mysql.com 2007-06-20 12:43:14 -07:00
parent f015b4332b
commit c6cc50960b
3 changed files with 52 additions and 6 deletions
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24
mysql-test/r/view.result
View file

@ -3476,4 +3476,28 @@ a1 c
2 0
DROP VIEW v1,v2;
DROP TABLE t1,t2,t3,t4;
CREATE TABLE t1 (a int, b int);
INSERT INTO t1 VALUES (1,2), (2,2), (1,3), (1,2);
CREATE VIEW v1 AS SELECT a, b+1 as b FROM t1;
SELECT b, SUM(a) FROM v1 WHERE b=3 GROUP BY b;
b SUM(a)
3 4
EXPLAIN SELECT b, SUM(a) FROM v1 WHERE b=3 GROUP BY b;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ALL NULL NULL NULL NULL 4 Using where
SELECT a, SUM(b) FROM v1 WHERE b=3 GROUP BY a;
a SUM(b)
1 6
2 3
EXPLAIN SELECT a, SUM(b) FROM v1 WHERE b=3 GROUP BY a;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ALL NULL NULL NULL NULL 4 Using where; Using temporary; Using filesort
SELECT a, SUM(b) FROM v1 WHERE a=1 GROUP BY a;
a SUM(b)
1 10
EXPLAIN SELECT a, SUM(b) FROM v1 WHERE a=1 GROUP BY a;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ALL NULL NULL NULL NULL 4 Using where
DROP VIEW v1;
DROP TABLE t1;
End of 5.0 tests.

24
mysql-test/t/view.test
View file

@ -3324,4 +3324,28 @@ SELECT * FROM t1;
DROP VIEW v1,v2;
DROP TABLE t1,t2,t3,t4;
#
# Bug #29104: assertion abort for a query with a view column reference
# in the GROUP BY list and a condition requiring the value
# of another view column to be equal to a constant
#
CREATE TABLE t1 (a int, b int);
INSERT INTO t1 VALUES (1,2), (2,2), (1,3), (1,2);
CREATE VIEW v1 AS SELECT a, b+1 as b FROM t1;
SELECT b, SUM(a) FROM v1 WHERE b=3 GROUP BY b;
EXPLAIN SELECT b, SUM(a) FROM v1 WHERE b=3 GROUP BY b;
SELECT a, SUM(b) FROM v1 WHERE b=3 GROUP BY a;
EXPLAIN SELECT a, SUM(b) FROM v1 WHERE b=3 GROUP BY a;
SELECT a, SUM(b) FROM v1 WHERE a=1 GROUP BY a;
EXPLAIN SELECT a, SUM(b) FROM v1 WHERE a=1 GROUP BY a;
DROP VIEW v1;
DROP TABLE t1;
--echo End of 5.0 tests.

10
sql/item.cc
View file

@ -1938,10 +1938,11 @@ bool Item_field::val_bool_result()
bool Item_field::eq(const Item *item, bool binary_cmp) const
{
if (item->type() != FIELD_ITEM)
Item *real_item= ((Item *) item)->real_item();
if (real_item->type() != FIELD_ITEM)
return 0;
Item_field *item_field= (Item_field*) item;
Item_field *item_field= (Item_field*) real_item;
if (item_field->field && field)
return item_field->field == field;
/*
@ -5627,8 +5628,7 @@ bool Item_outer_ref::fix_fields(THD *thd, Item **reference)
DESCRIPTION
A view column reference is considered equal to another column
reference if the second one is a view column and if both column
references resolve to the same item. It is assumed that both
items are of the same type.
references resolve to the same item.
RETURN
TRUE Referenced item is equal to given item
@ -5644,8 +5644,6 @@ bool Item_direct_view_ref::eq(const Item *item, bool binary_cmp) const
if (item_ref->ref_type() == VIEW_REF)
{
Item *item_ref_ref= *(item_ref->ref);
DBUG_ASSERT((*ref)->real_item()->type() ==
item_ref_ref->real_item()->type());
return ((*ref)->real_item() == item_ref_ref->real_item());
}
}